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daytona_74
Participant
October 25, 2024
Answered

Generative expand not honouring cmyk values

  • October 25, 2024
  • 1 reply
  • 624 views

Help needed please; Generative Expand is an excellent feature and is saving me loads of time and the results are excellent, however the new Generative Expanded part created has different CMYK values to the rest of the image area which will effect final print output. My current image only requires CMY but the extended part now has Black added, so not ideal. I've tried converting to RGB before Generative Expand but thats not working either. Ideas apprecitaed.

Thank you!

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Correct answer Stephen Marsh

That didn't clarify anything for me...

 

I presume that when you convert your CMY(K) image to RGB,  then Generative Expand, and then convert back to CMYK mode – then you find that K has been introduced when it wasn't there beforehand.  If so, this is expected unless your CMYK profile has no black generation.

 

What you can do is start with your CMY(K) file, then use Image > Mode > Multichannel, delete the blank 4th black channel, then Image > Mode > RGB. Run Generative Expand. Then Image > Mode > Multichannel, add a 4th white/blank channel, then Image > Mode > CMYK. This should retain the original CMY channel values and structure as you are bypassing ICC colour management. The caveat is that layers will be flattened when going through multichannel mode.

1 reply

Stephen Marsh
Community Expert
Stephen MarshCommunity Expert
Community Expert
October 25, 2024
quote

I've tried converting to RGB before Generative Expand but thats not working either.


By @daytona_74

 

What do you mean exactly by this?

D
daytona_74Author
Participant
November 1, 2024

Well, I've epeanded an image with Photoshop's Generative Expand and the CMYK values have changed in the channels on the extra part. I.e. Black was not part of the image but it is now. I have a CMY image as it is light and colourful and works without K (Black) and prints successfully too - thanks!

Stephen Marsh
Community Expert
Stephen MarshCommunity ExpertCorrect answer
Community Expert
November 1, 2024

That didn't clarify anything for me...

 

I presume that when you convert your CMY(K) image to RGB,  then Generative Expand, and then convert back to CMYK mode – then you find that K has been introduced when it wasn't there beforehand.  If so, this is expected unless your CMYK profile has no black generation.

 

What you can do is start with your CMY(K) file, then use Image > Mode > Multichannel, delete the blank 4th black channel, then Image > Mode > RGB. Run Generative Expand. Then Image > Mode > Multichannel, add a 4th white/blank channel, then Image > Mode > CMYK. This should retain the original CMY channel values and structure as you are bypassing ICC colour management. The caveat is that layers will be flattened when going through multichannel mode.

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